Appliance hand truck provided with stair-climbing attachment



Nov. 27, I956 A. H. HANSON APPLIANCE HAND TRUCK PROVIDED WITHSTAIR-CLIMBING ATTACHMENT Filed June 15, 1953 5 Sheets-Sheet 1 IN V ENTOR.

ALFRED H- HANSON Nov. 27, 1956 A H HANSON 2,772,096

APPLIANCE H'AMD' TRUCK PROVIDED WITH -ISTAIR-CLIMBING ATTACHMENT FiledJune 15, 1953 5 Sheets-Sheet 2 FIGS.

FIG 8.

INVEN TOR. ALFRED u. HANSON 9.4 5041 see Wad/3 Y- 44,

Nov. 27, 1956 2,772,096

A. H. HANSON V APPLIANCE HAND TRUCK PROVIDED WITH STAIR-CLIMBINGATTACHMENT Filed June 15, 1953 5 Sheets-Sheet 3 I09. I02. a

FIG- Ha- INVENTOR. ALFRED H. HANSON Wmvh A T TOQNE 15 Nov. 27, I956 A.H. HANSON 2,772,096 1mm HAND TRUCK PROVIDED mm ST R-CLIMBING ATTACHMENTFiled June 11$, -195a s Sheets-8heet 4 IN VEN TOR.

, wad/ h ATTORNEYS ALFRED H. HANSON Nov. 27, 1956 A. H. HANSON 2,772,096

- APPLIANCE HAND TRUCK PBQVIDED WITH STKIR-CLIMBING ATTACHMENT FiledJune 15, 1953 Siieets-Sheet 5 FIG. \7. FIG

ms 7 W ATTORNEYS United States Patent Q 11 Claims. (Ci. 2805.24)

The present invention relates to improvements in hand trucks and inparticular to a type of hand truck known as an appliance truck and usedfor manually lifting heavy loads up and over inclined irregular surfacessuch as flights of stairs, street curbs and the like.

Conventional appliance trucks normally consist of a truck frame withhandles, means such as a strap to bind a heavy load such as arefrigerator, or other heavy appliance to the truck frame, a pair ofwheels, and a glider or crawler unit for traversing a flight of stairsor similar obstacle. Such conventional crawler units generally comprisea plurality of small, centrally-mounted rollers or wheels which engageand roll over the edges of the steps, or alternately comprise an endlessbelt arrangement which turns over the step edges. Both such arrangementshave the disadvantage of providing a large amount of friction in theroller hearings or belt supports so that the operation of ascending aflight of stairs is difficult to perform by a single operator, if notimpossible.

It is an object of the present invention to provide an appliance handtruck which has improved roller units which are so constructed as topresent a minimum amount of friction, making possible manual operationby a single operator.

Another object of the invention is the provision of an appliance truckin which the roller units are movable as a whole relative to the truckframe to two selected positions, one of which is suitable for ascendinga flight of stairs or the like, and the other of which is suitable fordescending the stairs.

Still another object of the invention is the provision of an appliancetruck of the character described which is provided with automatic brakemeans which become effective, when the roller units are moved to theposition for ascending the stairs, to prevent the truck from rollingback down the stairs should the operator wish to rest the load, changehis grip, etc.

A further object of the invention is the provision of an appliance truckwhich has improved belt or strap means for. securing the load in asafely mounted position, these means being constructed to enable thebelt or strap to be tightened in an infinitely variable manner and toeliminate dangerous ratchet pawls, toggles, buckles, etc.

Other objects and advantages of the invention will be apparent in thecourse of the following specification when taken in connection with theacompanying drawings, in which:

Fig. 1 is an elevation of the appliance truck of vention as viewed fromthe rear thereof;

Fig. 2 is a section taken along line 22 of Fig. 1;

Fig. 3 is an enlarged section taken along line 3-3 of Fig. 2;

Fig. 4 is an enlarged section of a roller unit and adjacent parts, takenalong line 44 of Fig. 1;

Fig. 5 is a section taken along line 5-5 of Fig. 4;

the in- "ice Fig. 6 is a bottom plan view of one of the roller unitsshown in Fig. 1;

Fig. 7 is a top plan view of the same roller unit;

Fig. 8 is an end view of one of the roller units and adjacent parts ofthe hand truck as viewed along arrow F8 of Fig. 4;

Fig. 9 is a bottom plan View of an alternate type of roller unit whichmay be employed in the hand truck of Fig. 1;

Fig. 10 is a section along line 1010 of Fig. 9;

Fig. 11 is a side elevation of the lower portion of the hand truckshowing a roller unit of Fig. 9 and a brake assembly mounted thereon,with a part of the roller unit broken away and shown in section toreveal internal construction;

Fig. 11:: is a plan view of a portion of the hand truck shown in Fig.11, with parts thereof broken away and shown in section for convenienceof illustration;

Figs. 12-14 are diagrammatic side elevations partially in section,showing a hand truck in three successive stages of ascending a flight ofstairs;

Fig. 15 is a similar diagrammatic elevation partially in section,showing the same hand truck in the process of descending a flight ofstairs;

Fig. 16 is a sectional view of the lower portion of a hand truck showinga modified roller unit mounted thereon; 1

Fig. 17 is a section taken along line 17-17 of Fig. 16;

Fig. 18 is a bottom plan view of the roller unit shown in Fig. 16; i

Fig. 19 is a top plan view thereof; and

Fig. 20 is a perspective View of a pair of rollers of the roller unitshown in Fig. 16, the rollers being shown apart from the rest of theroller unit and joined by their mounting spring.

Referring to the drawings and particularly to Figs. 1-3, the appliancetruck has a metal frame comprising a pair of spaced flat side plates orstringers 10 and 11 connected intermediate their ends by a pair ofspaced cross bars 12 and 13 and also connected at their bottom ends byan L-shaped nose-piece or platform 14. Each stringer 16 and 11 has aninclined bottom edge 15 and a flat transverse flange 16 extending alongits front edge which may be formed by bending the front end of thestringer to form a perpendicular flange and securing an angle iron inalinement therewith, as shown in Figs. 2 and 3. The front end flange 16of each stringer 10 and 11 is covered by a tube 17 of flexible andresilient material such as rubber, to prevent injury to the surface ofappliances mounted on the truck. Each stringer 10 and 11 also has anopen triangular hand grip 18 at its top end, and a plurality ofelongated openings 19. spaced along its length, each opening 19 beingbordered by a pair of small circular apertures 20.

A cylindrical rod 22 is rigidly and immovably fixed adjacent each end tothe inclined bottom edges 15 of the stringers 10 and 11. The rod 22serves as the axle for a pair of wheels 23 and 24 which are rotatablymounted at the ends thereof.

A threaded shaft 25 is rotatably mounted between the cross bars 12 and13 by means of terminal stub portions 26 and 27 which extend'throughrespective bearingsZS and 29 in said cross bars. To the top stub portion26 is attached a handle 30 by means of which the shaft 25 may bemanually rotated. The threaded shaft 25 passes through a threadedcentral opening in a flat adjusting bar "31 which has pulley rollers 32and'33' mounted at each end. The adjusting bar 31 is utilized fortightening a retaining belt or strap 34 which passes around and holds anappliance mounted on the hand truck. In the use of the truck in moving aheavy appliance up or down a flight of stairs or the like, it isessential that the appliance be held tightly and securely against thetruck frame without loosening, since back lash and wobbling caused byloose- .ly-mounted appliances can be inherently dangerous in causing theoperator to lose his balance 'or the truck to get out of control. a l

-Fig. 1 shows a position which the retaining'strap 34 '-wouldassumewhenjit is arranged to hold a heavy object or appliance mounted onthe truck. 'Ihe'ends of-thestrap 34 are provided with respective hoks'35and 3 6 'which 1 are sized-for attachment to the; small apertures '20.of the stringers 1i) and 11. When an appliance is 'loaded on the similarmanner of operation. Each roller unit generally comprises a housing inwhich two adjacent longitudinal rows of rollers are mounted in staggeredrelation to each however, similar general structural characteristics anda other and with their bottom surfaces on'a common plane.

" Each roller is adaptedon contacting the edge ofa step beingtraversed,.to roil along'thehousing carrying the truck so that it restsupon'theplatform 14, the hook 35 at one end of the belt is attached toone of the apertures y 29 of the stringer 10. -The belt isthen passeda'round the pulley rolier-32pf adjusting bar 31. and is drawn through 7'one of thej elongated openings 19'of the stringet iti, thus formingbeltlsectionsor-segments'34a and 34b extending from opposite sides ofthe pulley roller 32. The free'end of the belt is then drawn 'around thefront and-sides of the appliance mounted on the truck and is drawnthrough an elongated opening 19 of'thestringer ll thus defining V beltis then looped over the roller 33 of adjustingbar 31 and back throughthe same opening 19 stringer 11, forming belt sections 34c and 34dleading from the pulley roller 33. At this point the free'end of thebelt is pulled so that the belt section 34a is drawnltight around/themounted'appliance and the terminalhook 36 is attached to the uppermostpossible-opening-Zil inthe stringer 18 so i that the adjacent endof thebelt is as taut as possible. The

'ffinal tightening of'the belt 34 is accomplished by turning j H ofthehandle-zdina direction to'cause the threaded shaft to turnrelative'to the threaded opening in'thet adjust-' ing, bar 31 andtoraise-the latter. It will be'no'ted that the belt sections 34a, 34b,34c and 34d will preyent the adjusting bar 31-from turning with thethreaded shaft 25. .When the 'adjust-ingbar 31 is raised it firsttensions the belt 34 by drawing the retaining section 34a thereoftightly around the mounted'appliance. This is efifected bylengtheningthe sections34q, 341534 0 and 34d. Considering the-sections34a'and-34bieading from the pulley roller, 32, if the adjusting bar31'is r'aised one inchffor example,- the sections 34a and 34bniustfeaclr be length eried approximately one inch; and sincethe-section 34b is fixed, it fresultsthat the section'34a-mustsupply-this inf creased length and must be drawn through itsopening 19 ba i mea 1 7 ing from the pulley rollerj33gwill'likewise both belengthcentral retainingstrap section34pz. The free end ofthe side walls 42and'43lrnay. each be provided with outturned lateral flanges 45 in orderto eliminate sharp edges-j l which may'cut or otherwise damage thestair'treads when 1 the center of the top wall '44. This central Wall46divides.

' the housing 41 into apair of longitudinal -rollerc0rnpartr t 35Zments47'and 48. In-each compartment-is mounted a. Hlongitudinally-aligned row of identical i rollers eachlo f i i the tworows having an equal number of, rollers. The;

step edge until thestep engages the next roller, in the adjacent row, atwhich time the first rolleri rises so that its bottom surface islocatedrabove'the commonplane of the, other rollers and the secondroller is leftfree to carry j the stair'edge to the next succeedingroller.

Figs. 4P8 show in 'detail'a pairof identical roller units 39 and 49.which are mounted in parallel alignment at 7 either side jof the machineinwardly and adjacent the respective stringersfit) and 11 Since.the'roller' units 39 and 4t? are identical in construction, forconvenience only one will be described fully, it being intended that de'scription Will apply equally to both units,-and the same.

reference numerals of-like parts will be applied to both units.

The roller unit 49, for example, has ahousi l 41,;which comprises a pairofspacedparallel, rectaugularside walls 42 and 43 joined atthe'ir upperends by an integralitop 7 wall 44; The housing41'fthus has anppen bottomend.

and open front and rear ends; The bottom edges ofth e the truck is inuse. l

The housing 41 also'includes;a'central,longitudinally-- J extendingpartition Wall 46, secured to and depending from drawings showi apreferred arrangement-in whichffour rollers areiprovided in each row,.the row containedfiin. compartment 47 consisting of rollers 50a,59b,.50c;and" 50d, and the row contained'in compartment48consistin ingof rollers 56559;, 59g and 5%.. V

V V The rollers 10f oneirow are mounted in staggered i'ela-- 1 tionshipto-the follersof the other row, with 'the'iends of the rollers ofopposite rows overlapping as clearly" shown-in Fig.6. 7

in stringer 19' by approximately two inches; 'Ihis -will' decrease thedength of the central-retaining section 346 hebelt' sections 34c'and'34d lead- V V ened by approximately one'incheach; so that the iunat itached belt section 134d is: drawmthrough its 7 elongated opening 19 in'stringer'll'ifor a'di'slta nce of approximately.

two inches, so that .the length o fithe belt retaining. section 7 34a isdecreased by an additional two inches, ora total oi substantially fourinches. Thus, the pulley arrangement provided by rollers 32 and33resu1ts the shprtening of the belt centralt retaining section- 344'by; an amonhta fi its substantially four times the -amou nt by which thej-ad} ustingbar31is raised s'o' thatit is generally: necessary'tO secureadjustmentof the belt.34 around the;appliance.

Each of the rollersis identical in construction com- 7 prisesa'cylindrical metal'core 51 .coverediby al'icylinder 52 ofjrubberorother-resilient materialhaving :a .rela--' tivelyhigh c'oefiicientofifrictiomiThe'imetal' core .51i I V has an'enlarge'd'ce'ntralcircularopening 53." i Y Each roller is normally held pres'seda'gainst the bot;7

tom surface of a respective flat metal block '54 tseeured' V i to theinner surface 10f: the "housing ltop 'wall 44, :The

blocks54 are longitudinallyaligned?in twofzgrespectivei I rows lo'cat'edwithin roller compartments 47;andi48,"as' a shown-in Fig. 4.; l5achblock '54"hasa 'lengthwhich'is in less thanfthe diameter of a roller;.and the: blocks in" the 7 1 V samerow are spacedfronfieach fothenbyra-f'suificient block and p artiallyienter t Thisarrangem'ent has theadditional, advantage'of cans I ingtheblt to be pulle'd in or retractedfromzeach side of 1 the appliance withequal tension; unlike conventionalapif pliancetrucksinwhich the beltis fixed at-lone end sot'hat'; a whenit is tightened itmust scuff or rub against the apf pliance. Suchfriction, which'is causedi'by the warping'of thelbieltraround its edges;prevents properfbe'lt'tightening dist'ance to enable a rollerito rollpwr the corner its i 7 he spacebetween it'sa-blo'clr and I Each rollerisnormallyfheld press l t v V consistingof a rectangular opefn clip '55forrneid' o bent;

wire stock; the bottontend' bight of whichV eXtends thro gli l thecentralopening- 53. of the roller?The side i arms' 'oii j thejcli extend'slidahlythrfoughrespective small slots "56 in'the"housing'top3wallfi i;Se that the top end of said r clip locatedexteriorly of said-housing andaboveesaid top wall. The tQp'end bight of each clipSSis seated' in' 58 have'a central depending'dimple r ro eena which 'ac'ts' asia seat foroneend .ofiacoil sisaagjao rne i V other end of said coil spring 60 isseated on a similar dimple or projection located on the housing top wall44. The four rollers in each row are divided into groups 'of twoadjacent rollers for mounting purposes, the two rollers in each groupbeing mounted by means of their respective clips 55 to opposite ends ofone of the plates 58. Specifically, the rollers 50:: and 50b are mountedon one of the plates 58, the rollers 50c and 50d on another plate, therollers 50e and 50 on another plate, and rollers 50g and 50h on stillanother plate.

Each plate 58 is normally urged upwardly at its center by its respectivecompressed coil spring 60 so that the two clips 55 at the ends of saidplate are normally biased toraised positions in which their top endbights are spaced well above the housing top wall 44. This normalposition is illustrated by the plate 58 at the right hand side of thehousing shown in Fig. 4. In this position the plate 58 is substantiallyparallel to the upper surface of top'wall 44, the axes of the two clips55 are substantially normal to the top wall 44, and the bottom bight ofeach clip 55 is in engagement with the top inner peripheral area of arespective roller core 51 and presses the roller against thebottom'surface of its respective block 54. When the roller assembly isnot in use, all of the plates 58 and their associated parts are in thisnormal position, and since the blocks 54 are all made of a uniformthickness, the bottom circumferential surfaces of all the rollers are ona common transverse plane.

Since each plate 58 is mounted at its center on a coil spring 60, itwill be seen that the plate 58 may act as a lever, pivoting downwardlyat either end with the top of spring 60 acting as a fulcrum. Themovement of plate 58, however, is not a true lever action since as oneend of the plate 58 is lowered, the clip 55 at the opposite end of'theplate prevents this opposite end from lowering. The pivoting movement ofone end of the plate 58 is accomplished by further compressing of thespring 60.

The roller units 39 and 40 are mounted at the bottom of the hand truckframe at a slight angle to the stringers 10 and 11, in a manner whichwill be presently described.

When the truck is loaded with a heavy appliance, it is tilted by theoperator and drawn or pushed along on the wheels 23 and 24 until aflight of steps or the like are encountered. At the time, the operatorbacks the hand truck toward the steps until the roller units 39 and 40engage the corner or nosing of the first step. One of the rollers oneach roller unit 39 and 40 is thus in abutment with the step nosing orcorner, the particular roller depending upon the height of the stepriser, but generally being the end roller 5011. After the roller unitshave engaged the first step, the operator ascends the stairs, pullingthe hand truck after him, the roller units engaging each of the steps insuccession.

As a roller engages a step corner edge, its outer covering 52frictionally engages and holds to the corner edge,

and as the hand truck is drawn further upwardly, each roller unit 39 and40 moves relatively to its frictionally engaged roller which pivotsaround the step corner edge. In effect, this has the appearance of thefrictionally-en gaged roller moving relative, to the roller unit, andfor clarity of explanation, the roller action will be described as ifthis were the case. p

Fig. 4 shows one of the rollers 50 o f roller unit 40 in engagement withthe upper corner of the nosing N of a step S. As the roller unit'40moves upwardly ,'past the step S, the roller 50] being frictionallyengaged and held by the step corner merely pivots around this corner,but has the effect of rolling relative to the roller unit housing. Theroller 50 thus rolls along the bottom surface of its block 54 until itreaches the end of the'bl'ock, as shown in Fig. 4,'and begins to turnthe corner of the block 54, entering the open space between its blockand the next succeeding block in the same row. As the roller 50 entersthis space, it rises so thatits bottom surface is raised above thecommon plane of the bottomsurfaces ofthe other rollers in unit 40. e Thespacing of the blocks 54 is such that just as the roller begins to rise,the adjacent roller 50b in the opposite row has been moved intofrictional engagement with the corner edge of step S, so that the weightof the hand truck is shifted from roller 50 to roller 50b. As the roller50b begins to travel along its block 54, the roller 50f which is alreadylocated above the plane of the other rollers can clear the step S andsnap back to its original position centered on its block 54 undertension of its associated spring 60. The return of the roller 50 is madepossible by the fact that the step edge first engages the succeedingroller 50b at a point on its circumference above and to the right of itsbottom circumference, the point of engagement being shown in Fig. 4. Asthe roller 5% begins its rolling movement, the edge of step S travelsrelatively downward to the lowermost point of the circumference ofroller 5%, and since this point is on the common plane of the bottomcircumferential surfaces of the rollers and the roller 50f hadpreviously been brought to its raised position, the roller 50f is freeto snap back free of the stair S.

The main function of block 54, therefore, is to prevent simultaneouscontact of the stair nosing with two adjacent rollers. Such contactwould cause one of the rollers to over extend its normal or intendedtravel, causing it to interrupt the free motion of the truck when thelimit of its clip 55 is reached. In actual construction, the thicknessof the blocks 54 permits the rollers to drop slightly beneath the flange45 of the roller unit housing so that under no condition can the clip 55be strained or bent.

The roller 50b now travels through the same cycle as described inconnection with roller 50 and as it begins to turn'the corner of itsblock 54, it passes the step edge to the next succeeding roller 50e andthe cycle is repeated until the last roller 50a passes the step edge tothe wheel 24. The operator may then roll the wheel 24 over the corner ofstep S and upon the step tread, wheeling the hand truck along the steptread until the roller units engage the next step on which the raisingoperation is repeated.

Thus, as the roller unit 40 traverses a step, the step edge is in eifectpassed from roller 50h to roller 50d, to roller 50g, and so on insuccession until it finally engages the wheel 24. The same operation isperformed simultaneously by the rollers of roller unit 39 at the otherside of the truck frame until the stepengages wheel 23 on that side. Themovement of the truck along the step edge is a smooth, unbroken motionsince each roller engages the step edge at a point not far above thebottom circumferential surface or crest of the roller so that the handtruck is not raised appreciably as the step edge travels to the bottomsurface of the roller. The raising operationis also an easy one evenwith a heavy load and can be performed with a single operator. This ismade possible by the fact that the force exerted on each rollerissubstantially tangential to it, enabling the roller .to roll freelyalong its block. In contrast, in appliance trucks having rollers mountedfor rotation on a central axis, the force is mostly radial, beingconcentrated on the bearing axis of the roller and making rotation ofthe roller diflicult.

The roller units 39 and 40 are mounted on the hand is loosely attachedso that the roller unit housing may have a limited pivoting movementwith the bolt 61 as its pivoting axis. The other end of each roller unithousing has a fixed pin 65 secured to and .extending laterally betweenits sidewalls 42 and 43. The looped end of a flat plate 66 rotatablyencircles the pin 65. The opposite looped end of said plate 66 rotatablyencircles a pin 67 sevens .fiigedfb etween the'two side arms of arectangularbraiilget 58* of U shaiqiidycross-section. The ma masattached 7 to each roller unit are {rigidly mounted at the opposite.

ends of a crankqbari69'which'hasa bowed central-section 70 and planarends'which are journalled in the stringers V '10 and llg' asshownin'Figs, land 3.

T he roller units 39 and-40 may bemovedsimultaneously betweenftheir,extended "position-shown in full line in Fig.4; andth'eir retractedposition shownin broken line.

' In the extended:position; the"brackets68 are substantially may Ebesetin their retracted positions in Which-substan- Inthe normal-useiofthe-hand truck fol-carrying aload 7 over a level ground surface, Itheroller 7 units '39 and 40 -wheels -23 tially their entire'housing'sareltinset between the respec- V tive 'stringers 10 and' ll andoutofftheway of the operators feet as'she pushes'the truck. Thisretractedposition is also'used when descending'a flight of stairs, aswill be presently described.

retracted positions while. the operator is in the act-0f V rearwardlyaway from the wheel:surfaces,'..and:;spacing the -be velledzedgessl fromthe inner wheel circumfer- 1 The roller units 39 and 40 may be brought'toQtheir' pushing or pulling the truck. For this purpose the "bowedcentral portion of crank .bar 69 is engaged by the operators foot andturned untilit-is directed up- 'er-s 10 and-'11, the*flat plates 66pivoting with relation 7 r to boththe brackets 68ian'cl the rollerunits, and taking the position shown'inbroken line in Fig. 4. Inarriving at this position, the'plates fifi'can'y. the endsof the re-182g Landfill. The topwallof'eaich rollerunit channel S6, and 87 isinterrupted -by arseriesof evenly spaced spective roller units 39 and 40upwardly; pivoting said roller units to their fully retracted positions"shown in broken line in Fig. .4. In this retracted position, the rollerunit hou'sing-suare substantially aligned with the stringers 10 andl land their rollers project onlya short distance '7 7 'behind' saidstringers.

When the roller units are pivoted to their fully retracted position,further inward pivoting is prevented by contact between flthefc'rankbars 69 and the end of the roller unit housings at .a 'respective pointsindicated by reference numeral 71 in Fig. 4. When the roller unitsarepivoted to their extended positions, furtherturning movement isprevented-by engagement of the flat plates 66: with thebottoin edges ofbrackets68 at contact points designated by reference numeral 72. Eachflat plate 66 hasan angular bend 66a slightlybelowits center, so that inith e -extended positionofthe roller units theiweight I ofitheloaditipon the roller'nnits'would maintain thetpla'te 166 ;in firmengagernent-withfthe edge-of bracket 68" at V icontactzpoint 72, and.thus prevent th'ebracket 68y-fronil' accidentally pivoting in" acounterclockwise direction toibringvthe rollcrfu nits back to'theirretracted positions.

'Thef'hand lruek may alsofbe pi'ovide'da-with i br a'ke the:stairs"should it get out of control or slip froin the lwhichgextendsthrough'the forward 611(l30f1'lh6 housing Qofeach respective-roller unit39 and 40,-and isfrigidly secured thereto. 'flse L -shaped niember isspaced from Z r the wallpfits roller unit housing by a'spacer sleeve'78.

i jijhis-pivotally-attached leg of memberi75 extends loosely" .throughaguide-lopp 79 which hasextensionsffillem-j" bracingieach respectivestrin ger l0 and 119.Thefree .transversezleg ofgeaeh ,L shaped member 75 has a: front: 1

f, bevelled edge 81; 'In the" Xe dedpositioniof thegroller f 93:wheres???i i a Y h r 605 i neansflto preizent the truck frorr'i rollingbackward; down 'tial surface pressedi-tagains't' said wallfportionwheerzs and '24. {Each edge-81is-bevelled-in such-a ingtoperation.However,-should the-hand truck'begin-to 's'lip 'downwardly, -or shouldthe operator. desire to -rest the truck on a stair tread, the .brakeprevents the wheels.

'23 and 24 from rotating forwardly or in a counterclock- '-WlS6direction. 'A tendency to so rotate 'would cause the bevelled edgesl tobite'firmlyintothe rubber-tires of the tion.

flight of stairs, or in the normal level-surface manner,

it is of course essential that 'thetwhe'els 23 and-24 beperar mitted torotatefree in a forwardor counterclockwise. direction. This isautomatically o accomplished when {the roller. units,are pivoted totheir retracted positions, this pivoting movement carrying theL-shapedmembers-75 ences. r j 7 V v i Figs. :9-11 show :a modified form ofroller, unit assembly with whichtthe hand truck may optionally be P1702"i V xvided. The roller. unit assembly comprises apair of identicalroller units 85, each of which has anintegral metal housing angula'rlybent in th'elshape shown 'inr Fig. 10 to providea' pairof spacedparallel longitudinalrollercham l'iBlSgfifi and-8'7, joinedbyanintegraLcenter platef88. Each roller; channel -S6fan'd 87sv containsaplurality of V rollerskarrange'd in 1a longitudinal'rowif In Figs;9-.and

l1; the channel 86 contains the rollers*8i9a; 89b,;.89.c.and 394; while7 the channel 87 contains -the; rollersji89e, 89f,

"openings'9il whichextend the 'width of the. channeland aresufficientlylongto enable a-rcllerto .fitntherewithin;

mountedposition idwhich; it is 'centeied uponfonepfjth top wall platformportions 9 1 withits nppe rfeirc mere be readily appreciar ithati thesewallfpor tio ppenings'j90 th'ere'between correspond to an haveftlie"sam'efunctio'n's as the blocks 54:0f the roller unitshown- 'in' Figs.457.,{Whenieach'rollen engages a step -e cl .S, 7 as is the case of theroller 89b' shown in' 'Fig; 1fl, -.its;resilient mounting spring93:expands,;alloyvingthe,rollerzto 7 travel alongiits wall -portiojn gluntil it reaches theladja 3 cent tppening 99. 'Whenithe;,rollerlbeg'insifto drop into I .7 I the. opening {9052 the step edge?willfen' gage the next roller,

inithis c'aseithe i'QlleIf89f, and'fithe roller 89b having risenabove'ithe plane'fbfathe.other rbllers is crea or-'15; step,

' edgegsand.is returnedfitofl its'ioriginal-'position by- H I and;preventing anymovementin'thatdirec- 7 #When the truck is used for"carrying a l oad down' a V V V integral piece of rubber or otherresilient .andfrictional material :and shaped as-showninlthe sectionalviews of'Figsi 9 and 10. t Each roller has convex side faces forming arelatively wide outer circumference of slightly less width than-the Yroller compartments '86, and 87, and an inwardly-tapered centralsectionj Each roller has a central hole'in which isset .a1hollow metal'eyelet 92. A coil spring 93" extends? through. theieyelet92of eachroller and; serves as are: I ts'ilie'nt central- 'mountingofsaid'roller. Thefspring -fi j hasclosed .lQOpsTQi at each endgwhichextend through V .jsnitably placed openings 95in. the-side wallsoftheroller; a channels 86 and :87? :A pairofiiia'et al. w ires -9 6extend through'lthe 'alin'ed spring end 100138 7943 'at the sides jofeach roller .tchannel; as .shownfin Figr 9 each Wire 96 :beingsecured'atleachend to the end rollers oli each rowl' 1 s 7 'Each rollerisx'thusinormally held :by its,spr in g 93i n a of the spring 93.'- Inorder to allow the springs 93 to expand as described, the side walls ofthe roller unit housings may be provided with outwardly-pressedelongated hollow bosses 97 at both sides of each spring 93, the ends ofeach spring 93 being secured at the center of said bosses. The bosses 97are sufliciently deep and sufficiently long to enable the sides of theexpanded spring 93 to be housed therein, thereby permitting the widecircumferential portions of .the roller to move in its respective rollerchannel past these spring portions.

The operation of the roller unit 85 is substantially identical to theoperation previously described in connection with the roller units 39and 40 of Figs. 1-9. Figs. 12-15 show in sequence the progress of theroller units 85 in ascending and descending a flight of stairs. Thisoperation will now be described in greater detail for a clearerunderstanding of the functioning of both the roller units 85 and thealternate roller units39 and 40 of Figs. 1-9. V Fig. 12 is adiagrammatic view showing aflight of stairs and a hand truck in theprocess of ascending these stairs. The hand truck is provided withroller units 85 such as those shown in Figs. 9-11. The hand truck isshown resting upon one of the step treads of the flight of stairs withthe roller unit 85 in its extended position and in engagement with theedge of the next step. Because the stair risers are short with relationto the lengthof the treads, the second roller 89b initially abuts thestair edge. Fig. 13 shows the same roller assembly 85 after the truckhas been pulled a short way upwardly along the stair edge. In this view,the wheel 24 has moved above the step tread, and the full weight of thetruck and and its load is upon the roller 89h and the correspondingroller of the opposite roller assembly which is not shown in theseviews. Since the roller 89h is frictionally held by the edge of thestep, upward movement of the roller assembly moves the top wall platformportion 91 away from the wheel 89h and moves the open space 90 towardthe area above the roller 89h. The roller 8% thus, in efiect rolls tothe edge of the wall portion 91 and around the corner of this wallportion partially into the opening 90, as shown in Fig. 12, rising abovethe plane of'the other rollers. Simultaneously with this rising, thenext succeeding roller 89c has moved into contact with the step edge.Fig. 14 shows the roller 89c as it is held by the step edge while theremainder of theroller assembly moves upwardly with relation thereto. Inthis view, the roller unit and truck have been raised slightly as theroller 89c rotates sufficiently to bring the step edge to the bottom ofits circumference. This raising of the roller unit 85 relative to thestep edge has permitted the mounting spring 93 to return the raisedroller 89h to its original position. Further upward movement of thetruck from the position of Fig. 14 will cause the stair edge to engagethe roller 89g, releasing roller 89c, and so on in succession until thewheel 24 engages the step edge and is rolled thereover so that it restson-the step tread, at which time the entire cycle is repeated with thenext higher step edge.

The arrow in Fig. 12 shows the path of the hand truck as it ascends thestairs. The arrow in Fig. 15 shows the path of the same hand truck whenit is'descending the flight of stairs. It will be noted that the angleof descent is more nearly vertical than the angle of ascent, since indescending the stairs, the roller units 85 'are set in their retractedpositions. This positions the wheels 24 and 25 well inwardly from theedge of the step when the wheels are lowered into contact with the steptread and is a safety feature of the hand truck, retarding the tendencyof the descending wheels to slip over the edges of the steps. When thetruck is descending the rollers move in the opposite direction and inthe reverse order than they do in the act of ascending the stairs.

The roller units 85 may be provided with the brake arrangement shown inFig. 8 or optionally, may be provided with an alternate type of brakewhich is shown in Fig. 11; This brake comprises a wedge-shaped blockengagement with the wheel 23.

One end or" a lever 102 is loosely and pivotally attached to the end ofblock 98 being held to a pivot pin 103 having a large clearance, the pin103 being secured to said block by a washer 104 and cotter-pin 105. Theother end of said lever 102 has anupturned lateral extension 102a. Asshownin Fig. 11a, the end of the crank bar 69 has an integral terminalcrank 106 which projects outwardly of the stringer 10. The leverextension 102a is pivotally attached to the end of this crank 106 bymeans of a washer.107 and cotter pin 108. It is preferred to provide acrank'106 at each end of the crank bar, 69, and a corresponding lever102 and block 98' with each of said cranks.

In the extended positions of the-roller units 85, the

cranks 106 are-directed downwardly so that their levers 102 place theresilient blocks 98 loosely wedged between the edge of wheels 23 and 24and the stringer platform 14 so that gravityholds the block and wheel incontact. In this braking position, the angle of inclination of theabutting edges of the blocks 98 is such as to prevent the wheels 23 and24. from rotating in a counterclockwise direction due to frictionbetween the block and wheel producing a progressive wedge action. Thewheels may turn freely n a clockwise direction because the block 98 isthen lifted out of its normal wedging position, such lifting beingpermltted by the loose pivot pin 103. When the roller units are broughtto their retracted position, the crank 106 shown in Fig. 11 rotatesin acounterclockwise direction,

raising and drawing the lever 102 rearwardly to the positron showninbroken line in Fig. 11. This movement of lever 102 causes the attachedblock 98 toslide rearwardly along the slot 101 and entirely out 'ofcontact with the wheel 23. The wheels 23 and 24 are thus-left free torotate freely when the roller units are in their retracted positions.

, Figs. 16-20 show another type of roller unit, a pair of which may beused in the hand truck of the invention, to performin the same manner asthe roller units previously described. This roller unit 110 alsocontains two longitudinal rows of friction rollers. Instead of providingmounting blocks for the rollers or top wall openings to enable one ofthe rollers to rise above the plane of the other rollers, this functionis achieved by shaping the rollers themselves as will be presentlydescribed. 7

The roller units 110 each have a housing 111 of rectangular shapesimilarto the housing 43 of the. roller units shown in Figs. l-8. Thehousing 111 has a central partition wall 112 dividing it into a pair oflongitudinally extending roller channels 113 and 114. Each said channelcontains a plurality of rollers 115. mounted therein by means of torsionsprings 1-16, and alternately staggered in the manner previouslydescribed;

Each roller 115 is made of a solid block of rubber cut into the shapeshown most clearly in Fig. 20. In plan view, the roller 115 isapproximately pear-shaped, the shape being formedby cutting away opposedsegments of a circular roller to provide a sm all arcuate top edge1115);, a larger arcuate bottom edge 1152; joined by oppositely inclinedstraight side edges 115a and 1150.. p

A steel wire clip 117 of inverted U-shape is internally molded in eachroller and ashort portion of the closed end of said clip 117 projectsabove said top edge 115a. The protruding section of each clip 117extends through a rectangular opening 120 in the top wall of roller unithousing 111 and isheld by the looped end of the torsion g'ag'es' anclholds at itsjopp'osite ends-thelclip117 of aroller fin 'the oppositdrollercliannel.

an one roller channel -and the clip of ai1 adjacent roller In Figl16,-one-of-the rollers-115in-rollerchannel 1-1 3 ,-ro1'1r effective to"pgrhit "litnited longitudinal niovement of; one r'ollerrelative toZ-theothers and to return said rolled-touts originaLposition,--rneanstog'raise lthe;

' isshown inengagement withthe corner edge of-a step; S,

as the-roller unit 110 is advanced 'up thestep. It'will be appreciatedthat the roller -1-15 -upo n first engaging the step edge will-rollrelatively to: the roller. unit housing 111 upon its top arcuate' edge115,; until it comes-to-the end "of saidtopedg'e1115 and reaches thejuncture of said edges ahdRtheside'dge115c of the roller; As "the sideedge 115c-comes1into conta'ctnwitli the'to'p edge of-the housing 111the-erigaged roller 115 in efliect beginslto rise above thef'plan'e orth'e'oth'er @llersandat thesame'tirne the step edgeornosingi's-engagedj-bythe next succeeding -roller' inthe opposite--rol1e1f-cliannel 114. -The spring 116 V themreturns the raised rollef115 to its' original position.

The operationof =the'rollfer units 110 in ascending or, 7

'descend' g a'ifli'ght of stairs is thus substantially the same 'as'thetwo' rollerunits previously described. I Y

' 'The' drawings are substantially toscale, andreterence is made theretotorturther disclosure.

bottom surface ;of each roller above the bottorn surface of-theothers'wheiifl said roller i s movedlongitudinally.

"2-.1An applianeehand truck for carrying a heavy "lead "up-a'fligh tofstairs-or the'like, comprising a frame supporting said'load;andapair'ofroller units mounted at each side"of1said'-frame,"eachrollerunit having a plurality of; longitudinally spaced rollers arrangedin successive overlappingwtaggered relationship with ad jacent'rollerslaterally'spaced from each other, eachsaid {roller resting upon an upperhousing portion .an d thef- "bottom;circumferentialsurfaces thereof,;bei ng 7on1 a, 115

f .cornrnon plane Y and jpositioned lo successively rengafge, a stepedge of 'the stairs as'the'hand'truck is. pulledfupwardly therealong,"resilient mounting means for each Allapplia'nce truck bodies,-whenascending fordescend- J ing stairs' orflthe like-assume an -angle-ofapproximately 7 l5' from the VQItlCfllWlllCh is createdjbythe operatorts lifting action-on the handles or grips at the top of each astringer or side plate. Such slight angular deviation fronr -thever'tical isihsufiicient to materially reduce the effort required tqlift the load; In conventional-appliance trucksgthe crawler or gliderassemblies corresponding to .theg roller'units-herein-are mounted.parallel' to the side plates or stringers. 'In the'hand truck of-thepresent 1nvention,=it will be noted thatthe' r'oller units in theirexten'ded positions extend outwardly :from the rear edges =of thestringers at an angle of approximately 2 0 thereto, which incombinationwith the aforementioned normal l 5;? creates-a total of- P deviationg-rso that the {extended roller'units aremore-nearly horizontal and agreater portion of the load weight is carried by the rollers rather common plane and pos' iti oned to successively engage a by the-operator.In actual practice the additional angle pfovided requires approximatelytwenty penc'ent less lifting force. The'angle herein shown may bemcreased to 7 further lessen the .lifting'effort. However; various stairdimensions limit'the maximum vangle. It has been found I thatbyreduction of total body weight, increased lifting "anglqandimprovedclimberor stairgliding units, the disclosed invention Y-reducs liftingef tort by approximately "one-third. 1

-n win bejals'o noted thatin all of the three types of roller'units'shown herein,-the rollers are embedded deep within the roller unithousing'so that only the l'owergportionsof. the rollersgproject fronithe houslng; {The roller unitsare thus adapted to withstand stronglateral thrusts which may result when the hand truck is turned'from oneflight of stairs to a perpendicularjflight of lstairsysothat 1dislddging the endless beltiotthe'gliderassembly -thus impairing theefiiciencyof the truck; In' the mstant-mvention, the rollers are guidedin'deep roller channels which.

- the'rollers engagethe second flight at an oblique-side angles Inconventional; appliance truckslsuch -la teral thrusts eften resultin-dam'aging; the roller bearings or prevent their turning or becomingdislodged. 1

pe thereof; claim: I

row staggeredlwith' adjacentrollers: of 'thefadjacent row,

. V '2 lQIn' an appliancehaidd trucktta roller' i 7" ing a housing,'-j aplurality ofirollersjmounted ir'rs'aid hqusing' in a pluralitypf rowswitligthe rollers'of each' rollerefiective tofperrnit each roller to beindependently en an difromj on d movement, byj i 'mst'ep edgegas saidhousing moves relative thereto, and Jneans; to raise the bottornjcircumference of said roller ;-ab a 9mm n plan a t en t cedin rol ten ee a i steped ea successive overlapping gstaggered relationship;withadjaeent rollers laterally t spaced from each other, -;each' said[roller resting upon an upper housing portion and the 7 bottom.circumferential surfaces thereof being on a stepV'edg of the stairs asthe hand truckisf pulled up- :fwai'dlyrtherealong, resilient. mountingmeans ,for each V t'roll'e'rf elfective:topermifeach roller to beindependently Qengagedand held frornlongitudinal movement by said a;step. edge. as said. housing-'moyesrelative thereto; and j meanstoraise thebottomfcircumference oftsaid roller '7 .above saidcommonplanelas the next-succeeding roller,

13,;;A pp1 n .hand t u i 0nc y nea ea y mad up ajflight of stairs or thelike, comprising a frame for s ppo t n s loadg Land. a Pa l c l r uni 1mounted a each s d pf said fram c roll r unit h ng .a plurality [oflongitudinally spaced rollers arranged in engages said{stepid-ge,fsaidtresilient mounting. means ,i i

being; also velfectivre to return each' raised roller. tou.its

original 'position.

Aniapplianceahandl truck. for c arryingtaload up fanddown: a. flight (ofstairs or: the, like,. said. hand truck comprising .a frame. forsupportingsaid lead, a plurality lof.wheels attachedgtowsaid frame, and.a}plurality;;of

aid rolle in itsrow relative to ltheother rollers, means I mor eat itdfi qws'a d' moun a q er being While preferred embodiments of theinveutiodhave 7 been shown and described herein, itfis 'obvious thatnu;- l merous jomissions, changes and additions -may be made iu theinvention without 'departing from the spirit and 1 Teach 19 said 'rdl trslhav ng ari r r ti router ,q tlmferentialsurface,and-resilienrmountingmeans for {each inouiiting means' 'for eachroller effective 'to' permit fp it n tpg n a suc v the e-o step osaidfl ght tof; istairsgas the roller; unit traverses said; stairs;gachrroller having;aresilient.outen surface for friction ial y pp u sais pji tl er-wh y said: r ll i el f-by r aid i tepte s z ro t n it i a mv me ho sin meve -a on said pt e L :1 appl an a uc ha ;aabdr time"cludin'g a pair of; s ide-rplateaia pair o f wheelskmounted; ,adjacent'the bottomsofgsaid side =p1at'es,'-;a pair toftrolle'r" 7 'units-mounted-adjacent -the 1ower ends of said 5 side 7 platesZandbehind-said -Wh6lS,6aCl1f of said roller units 7 comprising anelongated :housing and a plurality of rollers 7 mounted intsaid housing.in longitudinal rows,

the rollers of Leach. row fstaggeredlwith adjacent J rollersroftheadjacent; row, each-of;said rollershaving a. t onal t.=r: rrci mferntial 1 snar a r l ent I .Ztogaiseeaeh roller above the;plane;of theother rollers when said roller reaches thelimit of its;longitudina1limited' longitudinal movement of each roller relative to the others andto return said roller to its original position, means to raise thebottom surface of each roller above the bottom surface of the otherswhen said roller is moved longitudinally, and means for pivotallymounting said housings on said frame for simultaneous movement of saidhousing between a retracted position in which said housings aresubstantially parallel to and overlie said side plates, and an extendedposition in which the upper ends of said housings are spaced rearwardlyof said side plates and said housings are angularly disposed withrelation to said side plates.

6. An appliance hand truck having a body frame including a pair of sideplates, a pair of wheels mounted adjacent the bottoms of said sideplates, a pair of roller units mounted adjacent the lower ends of saidside plates and behind said wheels, each of said roller units comprisingan elongated housing and a plurality of rollers mounted in said housingin longitudinal rows, each of said rollers having a frictional outercircumferential surface, resilient mounting means for each rollereffective to permit limited longitudinal movement of each rollerrelative to the others and to return said roller to its originalposition, means to raise the bottom surface of each roller above thebottom surface of the others when said roller is moved longitudinally,and means for pivotally mounting said housings on said frame forsimultaneous movement of said housings between a retracted position inwhich said housings are substantially parallel to and overlie said sideplates, and an extended position in which the upper ends of saidhousings are spaced rearwardly of said side plates and said housings areangularly disposed in relation to said side plates, said mounting meansincluding a pivot connecting the lower ends of said housings to saidframe, a crank bar turnably mounted between the side plates and having abowed central section, a pair of brackets carried by said crank bar atopposite ends thereof, and a pair of plates pivotally connected at oneend to the respective brackets and at the other end to the top of therespective housings.

7. An appliance hand truck having a body frame including a pair of sideplates, a pair of wheels mounted adjacent the bottoms of said sideplates, a pair of roller units mounted adjacent the lower ends of saidside plates and behind said wheels, each of said roller units comprisingan elongated housing and a plurality of rollers mounted in said housingwith their bottom surfaces projecting from said housing and facingrearwardly, means for pivotally mounting said housings on said frame forsimultaneous movement of said housings between a retracted position inwhich said housings are substantially parallel to and overlie said sideplates for moving the hand truck forwardly in descending a flight ofstairs or the like, and an extended position in which the upper ends ofsaid housings are spaced rearwardly of said side plates and saidhousings are angularly disposed with relation to said side plates formoving the hand truck rearwardly in ascending a flight of stairs or thelike, and brake means for said wheels movably mounted on said frame andoperatively connected to at least one housing for movement into brakingengagement with said wheels when said housing is brought to its extendedposition, the brakemeans in their braking engagement being adapted torestrain the wheels from turning in a direction to permit forwardmovement of the hand truck.

8. In an appliance hand truck, a roller unit comprising a housing, aplurality of rollers mounted in said housing in a plurality of rows withthe rollers of each row staggered with the adjacent rollers of theadjacent row, each of said rollers having an arcuate upper surface, anarcuate lower surface, and a pair of planar side surfaces connecting theupper and lowersurfaces, the distance between said planar side surfacesbeing arcuate er than the distance between the upper and lower arcuatesurfaces, and spring means connected to the top of each roller andurging said roller to a position in which its arcuate top'surface abutsthe inner top surface of said housing, said spring means being effectiveto permit the top surface of back roller to turn against the housing topsurface until one of the planar side surfaces of the roller engages saidhousing top surface.

9. In an appliance hand truck, a roller unit comprising a housing, aplurality of rollers mounted in said housing in a plurality of rows withthe rollers of each row staggered with the adjacent rollers of theadjacent row, each of said rollers having an arcuate upper surface, anarcuate lower surface, and opposite planar side surfaces connecting theupper and lower surfaces, and resilient mounting means holding eachroller with its arcuate upper surface abutting the inner surface of saidhousing, the resilient mounting means being effective to permit limitedlongitudinal turning movement of each roller relative to the otherrollers and to return said roller to its original position, the distancebetween the planar side surfaces being smaller than the distance betweenthe upper and lower arcuate surfaces whereby the bottom surface of aroller is raised above the bottom surface of the other rollers when saidroller is moved longitudinally.

10. In an appliance hand truck, a roller unit comprising a housing, aplurality of rollers mounted in said housing in a plurality of rows withthe rollers of each row staggered with the adjacent rollers of theadjacent row, each of said rollers having an arcuate upper surface, anarcuate lower surface of greater length than said upper surface, and apair of inclined, planar side surfaces connecting the upper and lowersurfaces, the distance between the planar side surfaces being smallerthan the distance between the upper and lower surfaces, and resilientmounting means holding each roller with its arcuate upper surfaceabutting the inner top wall surface of said housing, the resilientmounting means being effective to permit limited turning movement ofeach roller relative to the others with the top arcuate surface of saidroller turning against said housing top wall to a position in which oneof the planar side surfaces engages said top wall and the bottom arcuatesurface of said roller is raised above the bottom surfaces of the otherrollers.

11. An appliance hand truck for carrying a heavy load up and down aflight of stairs or the like, comprising a frame for supporting saidload, and a pair of roll er units mounted at each side of said frame,each roller unit having a plurality of longitudinally spaced rollersarranged in successive overlapping staggered relationship with adjacentrollers laterally spaced from each other, each of said rollers having atop arcuate surface resting upon an upper housing portion, a bottomarcuate surface normally on a common plane with the other roller bottomsurfaces and positioned to engage a step edge of the sairs as the handtruck is pulled upwardly therealong, and a pair of planar side surfacesconnect ing the top and bottom arcuate surfaces, resilient mountingmeans for each roller effective to permit each roller to beindependently engaged and held from longitudinal movement-by said stepedge as the housing moves rela: tive thereto, the distance between theplanar side surfaces of each roller being smaller than the distance between the arcuate top and bottom surfaces thereof Whereby engagement ofa planar side surface of the roller with the upper housing portionraises the bottom surface of the roller above the common plane as thenext succeeding roller engages said step edge.

(References on following page)

